Risks

Before performing bone marrow aspirate or adipose tissue harvesting it is imperative to obtain informed verbal and written consent. A patient must fully understand the potential risks of the procedure, anticipated benefits, and alternatives. The risks include but are not limited to infection, skin necrosis, hematoma, seroma, skin deformity, soreness at the graft site and donor site, or pulmonary embolism.

Contraindications

Contraindications to performing a bone marrow procedure are severe anemia, active systemic or local infection at the site of harvest or injection, and active cancer, including but not limited to myelodysplastic syndromes. Contraindications for an adipose procedure would be active cancer and infection at harvest or injection site. Relative contraindications include pregnancy. Low body mass index (BMI) individuals require additional investigation for adipose procedures.

Medications

After obtaining consent for an orthobiologic procedure, reviewing any medications, supplements, or habits that may interfere with good cell acquisition or potential therapeutic effect is crucial. Medicines can have deleterious effects on adipose and bone marrow procedures. Most have not been studied for their effects on healing. Therefore, it is important for patients to take only medications that are necessary, which helps reduce polypharmacy. It is in the best interest of the patient to avoid certain medications in order to optimize the harvest. Such medications include: systemic steroids, inhaled steroids or steroid injections, fluoroquinolone antibiotics, HMG-CoA (3-hydroxy-3-methylglutaryl-CoenzymeA) reductase inhibitors or statins, and nonsteroidal antiinflammatory drugs (NSAIDs).

Corticosteroids can have deleterious effects on stem cells and healing and should be avoided for at least 6 weeks prior to the procedure. Fluoroquinolones can increase the risk of Achilles tendinitis and Achilles tendon rupture. Statins have a negative effect on stem cells and muscle cells. They have been found to impair the chondrogenic and osteogenic potential of Medicinal Signaling Cells (MSC, formerly Mesenchymal Stem Cells) and they increase cell senescence and apoptosis. If the patient is on a statin, they should supplement with coenzyme Q ₁₀ , which can help prevent some of the deleterious effects of statins on muscle cells. NSAIDs can inhibit bone healing, increase the risk of bone fractures, and increase bleeding. They should be held for at least 5 days prior to the procedure, and aspirin for at least 7 days prior. Holding of other antiplatelet medications and statin medications depends on the pharmacokinetics of the particular drug. If patients are on any anticoagulant medications, physicians should discuss with their prescribing doctors the procedure they will perform and determine if they can safely hold these medications.

Preparation

Patients should be instructed to hydrate in the days leading up to the procedure, especially for bone marrow aspiration. The patient should avoid eating solid food 4 to 6 hours prior to the procedure as a precaution against nausea but may continue to drink clear liquids. A review of the patient’s past medical history should be performed to determine if there are risk factors for anemia, and obtaining a hemoglobin/hematocrit on patients prior to a bone marrow aspiration should be considered. Results may impact the clinician’s decision to perform the procedure or how much bone marrow to extract.

The procedures to be discussed should be performed in a clean manner, using a sterile technique with the provider wearing sterile gloves, a facemask, and hair covering; consider using sterile sleeves or a gown. Baseline and post-procedure vital signs (blood pressure, heart rate, respiratory rate, oxygen saturation, and temperature) should be obtained; based on the vital signs, decisions can be made to proceed with the procedure. Patient monitoring with a pulse oximeter that includes heart rate monitoring is generally sufficient. Supplemental oxygen, blood pressure, automated external defibrillator (AED), and Crash Cart AED supplies should be available.

Anesthesia

Nonexperienced providers and patients may think that bone marrow procedures are very painful; however, in our experience, the procedure is well tolerated when adequate pre-procedure local anesthesia is provided. These procedures are routinely performed in the office setting outside of the hospital or surgical center and usually cause more anxiety than pain. Anxiety can lead to the patient having more muscular tension, which can increase discomfort, so relaxation is paramount. Less is more, and preferably music therapy is all that is necessary to control for anxiety. ^, In cases where patients have elevated levels of anxiety or other psychiatric diagnoses, the physician may recommend an oral anxiolytic of choice. The use of controlled substances may require more diligent monitoring. Patients with more extreme anxiety, minors, or patients with central sensitization may require the assistance of an anesthesiologist or certified registered nurse anesthetist (CRNA).

Site and Positioning

Extracting red bone marrow is usually best performed at the iliac crest. This region has been shown to have a higher yield of osteogenic progenitor cells compared to the tibia and calcaneus. Knowledge of the pertinent anatomy is important and the goal is to stay within the inner and outer tables of the iliac crest throughout the aspiration. The two typical approaches when aspirating from the iliac crest are the parallel and perpendicular approaches ( Fig. 5.1A and B ). For the perpendicular approach, you can access the posterior superior iliac spine (PSIS) with the patient in a prone or lateral decubitus position. For the parallel approach through the iliac crest, the patient may be supine for an anterior approach or prone for a posterior approach.

(A) Bone marrow aspiration in parallel to the ilium. (B) Bone marrow aspiration in perpendicular. Black box represents the ultrasound probe footprint and blue arrow represents the needle for aspiration.

A, From Hernigou J, Alves A, Homma Y, et al. Anatomy of the ilium for bone marrow aspiration: map of sectors and implication for safe trocar placement. Int Orthop . 2014;38[12]:2585–2590. https://doi.org/10.1007/s00264-014-2353-7 . B, From Bowen JE. Technical issues in harvesting and concentrating stem cells (bone marrow and adipose). PM&R . 2015;7:S8–S18. https://doi.org/10.1016/j.pmrj.2015.01.025

Bain and colleagues surveyed hematologists from 1995 to 2001. A total of 26 out of 54,890 reported adverse events from the perpendicular bone marrow biopsy approach for a rate of 0.05%. Of the 26 adverse events, 14 were reported as hemorrhage complications, with 6 requiring blood transfusions and 1 leading to death. Risk factors most often associated with these hemorrhaging events were aspirin use, myeloproliferative disorders, or both. Additional risk factors seen included warfarin use, disseminated intravascular coagulation, and obesity. This population likely has a greater risk of complications than a typical patient who will have a cellular treatment.

Our preferred approach is harvesting in a perpendicular approach from the PSIS with the patient prone. The posterior region of the iliac crest has been shown to have one of the thickest regions of bone. The average distance of the iliac crest is 24 cm. When determining which area to best access along the iliac crest, the concept of dividing the iliac crest into six different sectors ( Fig. 5.2A and B ) has been established to bring awareness of the anatomic differences in sector thickness and to help prevent violating neurovascular structures ( Fig. 5.3A – C ).

Iliac Sectors for Bone Marrow Aspiration.

(A) The iliac crest divided into six sectors has variability in sector thickness that must be understood when performing bone marrow aspiration. The iliac wing (three-dimensional reconstruction) was divided by drawing lines from equidistant points spaced along the rim of the iliac crest to the center of the hip. These lines were approximately perpendicular to the curve of the iliac crest. Six sectors were defined by these lines. Sectors 1 and 2, anterior part of the iliac bone; sectors 3 and 4, center part of the iliac bone; sectors 5 and 6, posterior part of the iliac bone. (B) The corresponding sectors can be found and marked on the patient by using the same technique and correspond in clinical practice to different zones of bone marrow aspiration according to the position of the patient. Three different approaches can be used to harvest bone marrow from the iliac crest: patient supine and anterior crest approach (sectors 1, 2, and 3), patient prone and posterior iliac crest approach (sectors 4, 5, and 6) and patient in the left or right lateral position allowing easier middle iliac crest approach (sectors 3 and 4).

From Hernigou J, Picard L, Alves A, et al. Understanding bone safety zones during bone marrow aspiration from the iliac crest: the sector rule. Int Orthop . 2014;38[11]:2377–2384. https://doi.org/10.1007/s00264-014-2343-9

(A) Diagrammatic representation of the sensory distribution for right posterior iliac crest. Procurement including the superior (L1 to L3) and middle (S1 to S3) cluneal nerves. Asterisk marks the posterior superior iliac spine. (B) Diagrammatic representation of the superior gluteal vessels. Asterisk marks the posterior superior iliac spine. (C) Diagrammatic representation of the course of the sciatic nerve. Asterisk marks the posterior superior iliac spine.

From Sittitavornwong S, Falconer DS, Shah R, et al. Anatomic considerations for posterior iliac crest bone procurement. J Oral Maxillofac Surg . 2013;71[10]:1777–1788. https://doi.org/10.1016/j.joms.2013.03.008

Anesthetic

A local anesthetic is required to control pain from the larger needle/trocar used in bone marrow aspiration. The typical anesthetic used is 1% lidocaine without epinephrine and up to 10 mL total per side. Alternatively, 0.25% to 0.5% ropivacaine can be used as well. This may be guided by the same imaging modality used for harvesting. A 22- to 27-gauge, 2 inch to 3.5 inch needle is typically used, depending on the chosen approach. Local anesthetic should be applied to skin at the needle entry site, soft tissue trajectory of the needle, and the surface of the bone/periosteum. The needle used to anesthetize the bone should never be longer than the needle used to harvest the bone marrow. This helps to avoid needle length mismatch in reaching the bone for harvesting. Never inject anesthetic through the trocar or needle used to aspirate marrow, as this can have a deleterious effect on cell viability. After the anesthetic is administered, the physician should wait at least 3 to 5 minutes until adequate anesthesia is achieved. Doing so greatly improves patient comfort.

Anticoagulation

Anticoagulant is necessary to prevent clotting of the marrow when performing an aspiration. If a proper anticoagulant protocol is not used, clots will form, preventing the acquisition, adequate isolation, and concentration of the desired buffy coat of the aspirate. Heparin is the desired anticoagulant. To calculate the proper dose, identify the amount of marrow desired and the syringes to be used for aspiration. Draw a ratio of 500 to 1000 IU of heparin per 1 mL of desired marrow amount. For example, if planning on aspirating 20 mL in a 30 mL syringe, draw 10,000 IU of heparin in the smallest-available volume. If planning on drawing 10 mL in a 10 mL syringe, draw 0.5 mL of heparin (10,000 IU/mL). An additional heparin mixture will be required for anticoagulation prior to bone marrow aspiration at each site. This will consist of a 5 mL syringe with 1 mL of heparin (5000 IU/mL) and 4 mL of normal saline or a 10 mL syringe with 1 mL of heparin (10,000 IU/mL) and 9 mL of normal saline. After each marrow aspiration, gently rock the syringe back and forth to ensure adequate anticoagulation.

Needles

Bone marrow aspiration can be obtained by manually placing a cannula ( Fig. 5.4 ) into the iliac crest, which requires a larger gauge due to the axial load needed. This is usually 11 gauge and can be placed by hand with a clockwise/counterclockwise maneuver while applying axial force or placement of the cannula/trocar against the bone and use of a mallet to force the cannula through the cortex. If performing a manual needle aspiration, typically an 11-gauge 4 inch trocar is used. Rarely, in some larger patients a larger trocar may be needed. We prefer a diamond-tipped needle as opposed to a slanted tip, which may have a greater tendency to slip off of the periosteum. Alternatively, when using a rotary-powered device to guide the aspiration, a smaller gauge needle, such as a 15-gauge 2.7 inch to 3.5 inch, may be used. Additionally, a needle assisted with a rotary drill has been shown to decrease procedure time and residual pain for the patient. Rotary devices decrease the stress on the wrist of the physician, especially when harvesting from multiple sites. Please refer to rotary device instructions on how to properly engage and disengage the needle for harvesting. It is important to have a good kinesthetic sense of how it feels to enter the marrow space. Adequate training including mentoring should occur prior to attempting bone marrow aspirations in live patients.

J-style bone marrow manual aspiration needle (11 gauge × 4 inches).

Syringe

Harvesting bone marrow from one site will likely result in a lower MSC count due to dilution with peripheral blood. Therefore, multiple samples from different areas should be acquired while harvesting. MSCs adhere to the trabeculae of bone at low volume pressures, resulting in minimal nucleated cells. Therefore, it is important to obtain the best-quality draws by not completely filling the syringes as you aspirate bone marrow. Hernigou and colleagues found that filling the syringe to 10% to 20% of its total volume resulted in an improved yield of MSCs and a better-quality harvest, and smaller-volume syringes resulted in a higher concentration of progenitor cells. Using 10 mL syringes yielded on average a 300% higher concentration of progenitor cells compared to a 50 mL syringe.

Techniques

For these procedures, other medical staff members should prepare the procedure tray prior to the patient entering the room. Please refer to the previous sections for consideration of needle choice, syringe size, anesthetic, and manual or rotary-powered needle advancement. Our preferred technique consists of 20 mL aspirations at each site using 30 mL syringes.